Vehicle driving mechanism



June 4,1946. c; EKSERGIAN 2,401,628

VEHICLE DRIVING MECHANISM Filed Oct. 30, 1943 PatentedJune 4, 1946 2Carolus L. Eksergian, Detroit, Mich assignor to Budd Wheel Company,Philadelphia, Pa a corporation of Pennsylvania Application October 30,1943, Serial No. 508,362

5 Claims.

This invention relates to vehicle driving mechanisms and particularly tothose of the track laying or endless tread type, in which steering ofthe vehicle is accomplished by varying the speeds of the tracks on theopposite sides of the vehicle.

An object of this-inventlon'is to provide an improved driving mechanismfor vehicles of this type constructed and arranged to produce a smoothand continuous braking operation when required, and to automaticallyprevent oversteering, that is, turning too quickly at high speeds.

These and other objects which will be apparent are accomplished by theinvention hereinafter described and illustrated in the accompanyingdrawing which shows a diagrammatic layout of a vehicle driving mechanismconstructed in accordance with one embodiment of this invention.

As illustrated, the invention is shown in connection with a drivingmechanism for tanks, tractors, or other vehicles of the track layingtype in which a power shaft a driven from any suitable source of power(not shown), operates through a differential t of conventional form todrive the plural driving means of the vehicle through countershafts land t which are connected to and drive, respectively. rotary members 9and it which in turn actuate the tracks on each side of the vehicle.Each countershaft has a braking mechanism for independently controllingits speed of operation.

Each mechanism includes a brake disc it comnested to the associatedshaft and brake shoes i2 mounted on operating yokes it supported onpivots it] and actuated by fluid pressure motor means It to producebraking engagement of the shoes it with the associated disc it, upondelivery of fluid pressure to the cylinder is. The two brake operatingcylinders are connected by fluid pressure lines it and I1, respectively,through pressure controlling valves I8 and i9, and lines it and 22 to asource 23 of fluid pressure. The delivery of fluid pressure from thesource 23 to the connecting lines is controlled byseparate manuallyoperated valves 24 and 25. The supply lines it and I'll have dump valves26 and 21 connected thereto for selectively reducing the brakingpressure in the lines l6 and II when desired.

Each driving mechanism operates a separate motor generator 28 and 29through gearing 8|, or the like. driven from the separate countershaftsI and 8, and an electric circuit 32 connects the. two generators.Included in the electriccircuit is a relay ll responsive to current flowfrom generator 28 to generator 28 for opera-tings solenoid anddump'valve 26 for the purpose of reducing 2 34 to actuate the valve l8'to shut oil! the pressure line 25 when a certain predeterminedpotential is established by the generator 28 due to excess speed thereofover generator 28. A second relay 35, which is responsive to currentflow from gens erator 28 to generator 28, controls a solenoid 36 foroperating the pressure dumpgyalve 26 in the line l6. A relay 31,responsive to current flow from generator 29 to generator 28, controlsthe solenoid 38 to operate the pressure valve l9 to shut oi! thepressure line 22 on the other side oi the tractor when the predeterminedpotential is established by the generator 29 due to excess speed thereofover generator 28. A relay 39, responsive to current flow-from generator28 to generator 28, operates a solenoid M for operating' the dump valve21 controlling the line H, Each of the four relays is a directionalrelay of conventional form, such as the polarized pole type, the arrowsindicating the direction of polarization, and is operated only uponcurrent flow in a certain direction in the circuit 32. Relays 33 and itare operated only upon current; flow through the outer branch oi thecircuit 32 irom generator 2t to generator at and thence to ground whilerelays iii and it are operated only upon current flow in the oppositedirection.

In operation, the relays Stand 31 are set to operate on a voltagedifierence between the two generators of five volts, for example, whilerelays it and as are set to operate on a potential of 6 volts, forexample. i

In operation, assuming it is desired to turn the vehicle while underway, the brake on that side will be applied for the purpose of slowingup the speed of the track on that side. Assuming the turn is to theright, the valve 26 is operated to apply the braking mechanism on thecountershaft 8 so as to reduce the speed of the driving mechanism it.This reduces the speed of operationof the generator in and results inthe generator 29 establishing a. higher potential in the circuit.

Should too great a braking pressure be applied,

the potential established by generator 219 will reach 5 volts which issumcient to actuate the relay 33, in turn operating the valve l8 throughthe solenoid at so as to shut oh the pressure line 20 and prevent theapplication of further Pressure to the associated braking mechanism.

If the diiierential in speed is such as to bring the voltage up to 6volts, for example, the dump relay is will be actuated to operatesolenoid 36 braking pressure in the pressure line It and relieve thebraking mechanism on the shaft I of 3 a part of the-braking pressure.Ordinarily the valve 26 will operate to bleed the fluid in theassociated brake cylinder rather than dump the entire pressure.

Operation of the relays 31 and 39 is similar and is produced when thespeed of the driving mechanism 9 is sufficiently less than that ofmechanism ID to cause the generator 29 to establish the necessarypotential in the electric circuit 32, for example, 5 and 6 volts,respectively.

It will be apparent that operation of the present invention is preventedwhen both brakes are applied together, unless they are applied with sucha differential in pressure as to produce turning beyond the degree forwhich the system is set. Also, the relays are of such type that theywill not be effective at vehicle speeds of less than a predeterminedamount, such for example, as five miles per hour.

What is claimed is:

1. In a steering control for vehicles, differentially-driven drivingmeans at the opposite sides of the vehicle, operator-controlled meansfor differentially braking said driving means and thereby causing thesame to be operated at differential speeds at the opposite sides of thevehicle to effect steering of the vehicle, and means responsive to apredetermined differential in the speeds of said driving means formodifying the action of the manually-controlled means to preventoversteering thereby.

2. In a steering control for vehicles, differentially-driven drivingmeans at the opposite sides of the vehicle, operator-controlled meansfor differentially braking said driving means and thereby causing thesame to be operated at different speeds at the opposite sides of thevehicle to effect steering of the vehicle, means responsive to apredetermined differential in the speeds of said driving means forlimiting the braking action on the driving means operating at theslow'erspeed due to the operator-controlled differential braking and furthermeans responsive to predetermined higher differential in the speeds ofthe driving means for reducing the braking action on said driving meansoperating at the slower speed.

3. In a steering control for vehicles, separate driving means at theopposite sides of the vehicle, a differential drive therefor, a separateoperatorcontrolled braking means for each of said drivin means includinga fluid pressure device, said separate braking means for permitting, atthe will of the operator, differential braking of the driving means onthe opposite sides of the vehicle to cause I them to operate atdifferent relative speeds to effect steering of the vehicle, andmeansresponsive to a predetermined difference in the rela-' tive speedsof said driving means for limitin the operator-controlled pressure ofthe braking means associated with the driving means operating at theslower speed due to differential operation of said braking means.

v4. In a steering control for vehicles, driving means on the oppositesides of the vehicle, a

difference in the relative speeds of said driving means for limiting thepressure of the braking means associated with the driving meansoperating at the slower speed due to differential operation of saidbraking means.

5. In a steering control for vehicles, separate driving means at theopposite sides of the vehicle, a differential drive therefor, a separateoperatorcontrolled fluid-operated braking mechanism for each of saiddriving means, said separate mechanisms permitting, at the will of theoperator, differential braking, of the driving means at the oppositesides of the vehicle to cause them to operate at different relativespeeds to effect steering of the vehicle, a separate electric currentgenerator operated by each of said driving means, an electric circuitconnecting said separate generators so that the potential established byone opposes that established by the other, separate shutoff and pressurereducing valves connected in each brake mechanism independent of theoperators control thereof, separate shut-off valve-controlling relaysresponsive to a predetermined potential difference between saidgenerators for limiting the braking pressure applied by the operator tothe driving means operating at the slower speed due to the differentialoperation of said braking mechanisms. and separate reducingvalve-controlling relays responsive to a predetermined higher potentialdifference between said generators for reducing the braking pressureapplied to said driving means operating at the slower speed.

CAROLUS L. EKSERGIAN.

